Medical images are an important component of the medical record generated during a patient's hospital stay or clinic visit. Unfortunately, these images represent a difficult-to-manage data source because of the extremely large size of the datasets involved. The NIH Clinical Center (CC), like most university and research hospitals, is attempting to solve the problem of consolidating medical images with the conventional alphanumeric medical record data in the Medical Information System (MIS) to more completely realize the goal of a comprehensive electronic medical record. Toward this end, DCRT, CC, and NCI are collaborating to develop a series of demonstration projects that explore image integration into the electronic medical record. The images of interest range in size from diagnostic electrocardiograms (16 Kbytes) through tomographic scans (256 Kbytes) to conventional film X rays (4Mbytes). Twelve-lead diagnostic electrocardiograms (ECGs) are automatically acquired, interpreted, and stored on magnetic disk using a Hewlett-Packard ECG Data Management System located in the CC. In order to transfer ECG diagnoses and the related waveforms from this minicomputer system to the MIS, a remote ECG workstation is being developed as a serial RS-232 gateway between the two systems. Because ECG waveforms are essentially binary images (black waveforms on white background), in which the number of equivalent black pixels is extremely low (approximately 0.1 percent), ECG waveform data are more efficiently stored and transmitted as time-ordered lists of 10- bit ECG amplitudes, rather than as 2.75K by 3K pixel images. Chest X rays appropriate for integration into the MIS as well as for transmission to the relevant outpatient clinic are routinely obtained within the Diagnostic Radiology Department. As an integral part of an image gateway we are now using a Vision Ten Rital system, which contains a gray-scale sheet film digitizer, and two Rital-compatible image display systems. Using the CC fiber optic network, communication of medical images between the Radiology Department's Film Library and remote sites is now possible. The weekly NHLBI Cardiac Surgical Clinic was the first outpatient clinic to routinely use chest films transmitted over this Ethernet pathway. Future plans include the connection of two General Electric CT scanners into the Vision Ten image transmission and display environment. This will be accomplished via ACR-NEMA, ethernet-based communication links to dedicated image servers, which will be added to the teleradiology network. In addition, we are planning a prototype high-speed image communication network based on Asynchronous Transfer Mode (ATM) Switch technology. The ATM Switch will allow 155 Mbit/sec multi-media communications between users. The CT images to be transmitted via this system will be obtained from the CT scanners' dedicated image servers. Custom-designed Radiology Consultation Workstations will be located in the CC's Diagnostic Radiology Department, as well as in NCI's Radiation Oncology Branch. Real-time consultation sessions between a radiologist and a radiation oncologists should contribute to the rapid development of radiation therapy treatment plans.